There's a terrific idea at the heart of "Pleasantville," and it's a shame that its creator, "Big" screenwriter Gary Ross, can't figure where to take it.

The premise is cute and high- concept: A modern teenager, played by Tobey Maguire, is hooked on a black-and-white sitcom from the '50s called "Pleasantville." When he and his sister (Reese Witherspoon) get sucked into their TV set and become citizens of that bland suburban world, they bring havoc by introducing hipness, sensuality and '90s attitudes on sex.

For David (Maguire), who feels oppressed by the cynicism of the late '90s, a dip into Pleasantville is a dream. For Jennifer (Witherspoon), it's hell.

Gradually, the siblings discover Pleasantville's secrets: The rest rooms have no toilets, the library books are blank, nobody knows about sex and the town has one road that just loops 'round and 'round, with no link to the outside world.

So far, so good -- but when Ross grasps for allegorical import, "Pleas antville" bogs down. As the siblings share knowledge of the "real" world and the Pleasantvilleans start morphing from black and white to color, the town becomes divided.

Ross wants to say something about discrimination and differentness, but he's at cross-purposes. Given that he's established the people of Pleasantville as cardboard clones, and considering that we know that David and Jennifer will go back to the '90s, it's hard to get worked up about the community crisis over "colored" versus black and white.